A fuel cell system comprises a stack of cells which, when coupled, provide a desired power output. Once assembled, the fuel cell system has a cathode side and an anode side which can be treated as two separate systems. An electrolyte (or ion-conducting) separator is positioned between the cathode side and the anode side. During operation of the fuel cell system, oxygen-containing gas (e.g., atmospheric air) passes through the cathode side, hydrogen-containing gas passes through the anode side, and the gasses react to generate electricity.
The hydrogen-containing gas is typically supplied from one or more bottles at a high pressure (e.g., about 2000 psi to about 3500 psi). As the anode side usually requires the introduction of the hydrogen-containing gas at a significantly lower pressure (e.g., about 5 psi to about 6 psi), the gas must pass through one or more pressure-reducing devices (e.g., regulators) upstream of the fuel cell stack. A flow-controlling device (e.g., a solenoid valve), downstream of the pressure-reducing devices, can be selectively opened to allow the passage of the hydrogen-containing gas to the fuel cell stack. Other components (e.g., manual shutoffs, pressure readers, over-pressure protection, etc) are often also necessary or desired.